1. Field of the Invention
The present invention relates to a semiconductor memory circuit, more particularly, to a semiconductor memory circuit having PROM cells utilizing an electrical breakdown of each insulator thereof for programming.
2. Description of the Related Art
Conventionally, three types of programmable cells are provided for One-Time-PROMs, i.e., a fuse type cell, a junction-shorting type cell, and an EPROM cell. Recently, however, a new programmable cell known as a Breakdown of Insulator for Conduction cell (BIC cell) has been developed.
This BIC cell utilized an electrical breakdown of an insulator for programming, and has an advantage in that it can be programmed within 1 .mu.sec. Therefore, if a PROM cell is composed of a BIC cell and a MIS transistor, it becomes possible to realize a high speed programming operation. However, problems have arisen in the prior semiconductor memory circuit using the BIC cell and the MIS transistor in that in this prior semiconductor memory circuit, since an insulator of the BIC cell is broken after a high potential application, a large amount of power is unnecessarily consumed because a large current continues to flow after the program process is completed.